/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:		arm_cmplx_conj_f32.c
*
* Description:	Floating-point complex conjugate.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
* ---------------------------------------------------------------------------- */
#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @defgroup cmplx_conj Complex Conjugate
 *
 * Conjugates the elements of a complex data vector.
 *
 * The <code>pSrc</code> points to the source data and
 * <code>pDst</code> points to the where the result should be written.
 * <code>numSamples</code> specifies the number of complex samples
 * and the data in each array is stored in an interleaved fashion
 * (real, imag, real, imag, ...).
 * Each array has a total of <code>2*numSamples</code> values.
 * The underlying algorithm is used:
 *
 * <pre>
 * for(n=0; n<numSamples; n++) {
 *     pDst[(2*n)+0)] = pSrc[(2*n)+0];     // real part
 *     pDst[(2*n)+1)] = -pSrc[(2*n)+1];    // imag part
 * }
 * </pre>
 *
 * There are separate functions for floating-point, Q15, and Q31 data types.
 */

/**
 * @addtogroup cmplx_conj
 * @{
 */

/**
 * @brief  Floating-point complex conjugate.
 * @param  *pSrc points to the input vector
 * @param  *pDst points to the output vector
 * @param  numSamples number of complex samples in each vector
 * @return none.
 */

void arm_cmplx_conj_f32(
    float32_t* pSrc,
    float32_t* pDst,
    uint32_t numSamples)
{
	uint32_t blkCnt;                               /* loop counter */

#ifndef ARM_MATH_CM0

	/* Run the below code for Cortex-M4 and Cortex-M3 */
	float32_t inR1, inR2, inR3, inR4;
	float32_t inI1, inI2, inI3, inI4;

	/*loop Unrolling */
	blkCnt = numSamples >> 2u;

	/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
	 ** a second loop below computes the remaining 1 to 3 samples. */
	while(blkCnt > 0u) {
		/* C[0]+jC[1] = A[0]+ j (-1) A[1] */
		/* Calculate Complex Conjugate and then store the results in the destination buffer. */
		/* read real input samples */
		inR1 = pSrc[0];
		/* store real samples to destination */
		pDst[0] = inR1;
		inR2 = pSrc[2];
		pDst[2] = inR2;
		inR3 = pSrc[4];
		pDst[4] = inR3;
		inR4 = pSrc[6];
		pDst[6] = inR4;

		/* read imaginary input samples */
		inI1 = pSrc[1];
		inI2 = pSrc[3];

		/* conjugate input */
		inI1 = -inI1;

		/* read imaginary input samples */
		inI3 = pSrc[5];

		/* conjugate input */
		inI2 = -inI2;

		/* read imaginary input samples */
		inI4 = pSrc[7];

		/* conjugate input */
		inI3 = -inI3;

		/* store imaginary samples to destination */
		pDst[1] = inI1;
		pDst[3] = inI2;

		/* conjugate input */
		inI4 = -inI4;

		/* store imaginary samples to destination */
		pDst[5] = inI3;

		/* increment source pointer by 8 to process next sampels */
		pSrc += 8u;

		/* store imaginary sample to destination */
		pDst[7] = inI4;

		/* increment destination pointer by 8 to store next samples */
		pDst += 8u;

		/* Decrement the loop counter */
		blkCnt--;
	}

	/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
	 ** No loop unrolling is used. */
	blkCnt = numSamples % 0x4u;

#else

	/* Run the below code for Cortex-M0 */
	blkCnt = numSamples;

#endif /* #ifndef ARM_MATH_CM0 */

	while(blkCnt > 0u) {
		/* realOut + j (imagOut) = realIn + j (-1) imagIn */
		/* Calculate Complex Conjugate and then store the results in the destination buffer. */
		*pDst++ = *pSrc++;
		*pDst++ = -*pSrc++;

		/* Decrement the loop counter */
		blkCnt--;
	}
}

/**
 * @} end of cmplx_conj group
 */
